Bug-eating evangelists like to talk about how crickets are caloric magic, claiming the insects can transform table scraps into a crunchy, healthy protein. A new study debunks at least one aspect of what’s being touted everywhere as the food of the future: Crickets are not the resource-efficient calorie-making machines we believe them to be.
The nutritional and environmental benefits of crickets have been overstated, reported two researchers at the University of California, Davis in the journal PLOS ONE. “Everyone assumes that crickets—and other insects—are the food of the future given their high feed conversion relative to livestock,” entomologist Michael Parrella tells Entomology Today. “However, there is very little data to support this, and this article shows the story is far more complex.”
The claim that’s addressed by the study is what’s called the protein conversion rate: How much plant matter must be consumed by the animal to make a certain amount of protein. A UN study that praises insect-eating as a sustainable choice points to crickets as a key nutritional source on a resource-depleted planet (that’s why they’re a staple in much of the world). The study says that cows would require six times as much feed to produce the same amount of edible protein as crickets could produce. Animals like pigs and chickens would require twice as much.
To test this theory, scientists fed crickets five different diets, from a low quality diet of of straw and chicken manure to a high quality diet of grain-based livestock feed. Just like in many other animals raised to be eaten, those fed a higher quality (and more expensive) diet with the largest amount of food grew largest and fastest. Those fed the lowest quality food did not even grow large enough to be harvested, and much of the cricket populations died.
This is troubling because the same UN factoids are being bandied about in many places right now due to the drought debates around water-to-food growing ratios. An essay by the founder of Bitty, a company that makes cricket protein foods, made the rounds recently urging Californians to cut back on beef and nuts, and explore insects instead as a conservational diet choice. This kind of advice might not tell the whole story in light of the UC Davis study—the crickets would still need to be consuming livestock-quality feed, and lots of it, to plump them up enough to eat.
But all is not lost, entomophagists. The study says that another bug, the black soldier fly, might actually be may be a far more efficient protein-producer. There are actually plenty of projects exploring the viability of raising the larvae in tiny fly farms at home.
Although they may not deliver as much protein as originally thought, one cricket fact remains true: Fried up with a little oil and salt, they are exceptionally delicious.
Photo by tamir niv